[llvm-dev] [cfe-dev] compiler-rt RFE to support creating profraw for each Shared Library

[Oza, Hiral via llvm-dev]

Hello Vedant,

> could you share some of the use cases for this feature? > What were the pros/cons of any alternatives you considered (e.g. the %m/%c modes)?

We are taking coverage of shared libraries (i.e. Linux .so) and dumping coverage into files corresponding to SO's filename.
With this proposed patch, will get coverage as below for sample code (pls refer compiler-rt/test/profile/Linux/instrprof-shared-nProfraws.test):
libhi.so  -> will dump into libhi.so.profraw
libhello.so -> will dump into libhellp.so.profraw
main.out -> will dump into main.out.profraw

Regarding '%m or %c: (from https://clang.llvm.org/docs/SourceBasedCodeCoverage.html): %m is expands instrumented binary's signature (and with "%Nm" dumps into poll of N profraws) and %c seems very different from proposed "%n".

Basically with proposed patch (i.e. using "%n") one can get one-to-one mapping of Shared Library and generated .profraw.
This makes backtracking and instrumenting final-binary based on feedback easy.

Please let me know in case of further queries or any changes in proposed patch.

Thank you.
-Hiral

From: cfe-dev <cfe-dev-bounces at lists.llvm.org> On Behalf Of Oza, Hiral via cfe-dev
Sent: Wednesday, 22 September, 2021 18:56
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Subject: [cfe-dev] compiler-rt RFE to support creating profraw for each Shared Library

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Greetings!

Please review our patch compiler-rt RFE patch here -- https://reviews.llvm.org/D110232

This patch is about creating profraw for each Shared Library.

<patch_info>

SBCC RFE: Support SBCC for Shared Library



SBCC RFE: Support SBCC for Shared Library

Using '%n' format parameter for profile name templates, to insert the full

path of the current shared object into profile file names.



Internally using a linked list to gather all profile dumping functions

(there is one defined in each shared object) so they can be invoked with a

single function call.  Ensure the resulting directory paths are created

prior to dumping.
</patch_info>

Thank you in advance for your kind review.
-Hiral

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